1. Technical Field
The present invention relates to novel thrombopoietin receptor activators, which are organic amine salts of 3-{[((2E)-2-{1-[5-(4-t-butylphenyl)-4-hydroxy-3-thienyl]ethylidene}hydrazino)carbonothioyl]amino}benzoic acid. The compounds of the present invention are useful as therapeutic agents for diseases accompanied by abnormal platelet counts or platelet increasing agents.
2. Background Art
3-{[((2E)-2-{1-[5-(4-t-Butylphenyl)-4-hydroxy-3-thienyl]ethylidene}hydrazino)carbonothioyl]amino}benzoic acid (hereinafter referred to as Compound A) is useful as a thrombopoietin receptor activator. Compound A is disclosed in WO04/108683 (Patent Document 1) and JP-A-2006-527187 (Patent Document 2) as a compound encompassed by a general formula along with its tautomers, prodrugs or pharmaceutically acceptable salts or solvates thereof. Compound A is disclosed in US 2006/094694 A1 (Patent Document 3) as a specific compound. Regarding salts of Compound A, although alkali metal salts and the like are mentioned as pharmaceutically acceptable salts, no specific salts are disclosed as working examples.